As the development of nanoscale mechanical, electrical, chemical and biological devices and systems increases, new processes and materials are needed to fabricate nanoscale devices and components. This is especially true as the scale of these structures decreases into the tens of nanometers. There is a particular need for materials and methods that are able to duplicate nanoscale patterns over large areas with perfect or near-perfect registration of the pattern features. Block copolymer materials are useful in nanofabrication because they self-assemble into distinct domains with dimensions in the tens of nanometers or lower.
However, existing methods of using block copolymer material suffer from several limitations. Approaches that rely solely on copolymer self-assembly suffer from defects in the patterns. One approach to nanopatterning with block copolymers combines chemical patterning of a substrate by advanced lithographic techniques with the self-assembly of diblock copolymers. The chemical pattern directs the self-assembly of the diblock copolymer, producing perfect or near-perfect duplication of the pattern and registration of the pattern features over a large area.
However, thus far the use of directed self-assembly has been limited to replicating the two-dimensional pattern of the substrate in the diblock copolymer film.
What are needed therefore are methods and compositions for creating block copolymer films with more complex morphologies.